Turbo vs. Supercharger.

[jdbubb at ix.netcom.com (Dan Bubb)]

Fact: Roots type superchargers are ~50% efficient. Lysholms are better, although I can't find any data saying how much better.
Turbochargers, if run in the proper range can be over 70% efficient.
Like it or not, for a given pressure ratio, the air coming out of a supercharger is going to be hotter!

The fact that the turbine housing of a turbocharger is glowing red hot doesn't mean the compressor side is equally as hot. There's a center section that is oil cooled as a minimum and in most cases also water cooled. THAT isn't glowing and probably isn't much over 250'F even under high load! Probably not a whole hell of a lot hotter than the supercharger body (sitting in most cases right behind the radiator!)
Yes, the close proximity of the hot turbine to the compressor will heat the air charge. But, only actual measurement will tell if it heats it enough to match the less efficient supercharger's air heating capability!
Dan
  ----- Original Message ----- 
  From: L F 
  To: Dan Bubb ; Mike Smith ; car 
  Sent: Monday, June 30, 2003 9:00 PM
  Subject: Re: Turbo vs. Supercharger.


  Dan,
   Point of interest;
    about the implied higher intake air temps with super?

  Ever see a photo of a turbo glowing orange hot?

  Don't see many red-hot superchargers any more.....